1. Field of the Invention
The present invention relates to encoding apparatuses.
2. Description of the Related Art
A technology has been developed in which an upper-layer image formed of pixels having a smaller amount of information than pixels constituting the original image is generated and a lower-layer image which is almost the same as the original image is generated from the upper-layer image. The assignee of the present invention has proposed the technology in Unexamined Japanese Patent Publication No. Hei-8-206552 and in the corresponding U.S. application Ser. No. 893,202, filed on Jul. 15, 1997, now U.S. Pat. No. 6,477,278, which is hereby incorporated by reference.
In the applications, a pixel value of the lower-layer image is obtained by calculating a prediction expression formed of a linear combination of the pixel values of prediction taps where an aimed-at pixel of the upper-layer image is placed at the center and the prediction coefficients corresponding to the class code into which the aimed-at pixel is classified. The class code of an aimed-at pixel is determined from the pixel values of class taps formed of the aimed-at pixel and pixels disposed in its vicinity.
Therefore, to generate an upper-layer image which allows a lower-layer image almost the same as the original image to be generated, it is ideal that pixel values and class codes (prediction coefficients) are made more appropriate at the same time.
To make both pixel values and class codes (prediction coefficients) more appropriate at the same time, however, it is necessary to change the pixel values of all pixels in the upper-layer image at the same time. This requires a vast amount of calculations. Therefore, it is practically impossible to make both pixel values and class codes (prediction coefficients) more appropriate at the same time.
When pixel values are made more appropriate after class codes (prediction coefficients) are made more appropriate, for example, since the class codes are determined from the pixel values of an aimed-at pixel and other pixels, the class codes made more appropriate in advance are changed. It is impossible that either pixel values or class codes are fixed and then the other is made more appropriate.
Accordingly, it is an object of the present invention to generate an upper-layer image (signal) which allows the original image (original signal) to be recovered, by making both pixel values (sample values) and prediction coefficients more appropriate without being affected by each other.
The foregoing object is achieved in one aspect of the present invention through the provision of an image-signal conversion apparatus for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, including intermediate-image-signal generation means for generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; intermediate-image storage means for storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; prediction-coefficient storage means for storing a prediction coefficient linked to each class code; prediction-coefficient update means for generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and for updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage means; class-code update means for selecting a more appropriate class code linked to the aimed-at pixel in the intermediate-image signal, according to the intermediate-image signal, the prediction coefficient linked to the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, and the original-image signal, and for updating the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, stored in the intermediate-image storage means; and determination means for determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in another aspect of the present invention through the provision of an image-signal conversion apparatus for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, including intermediate-image-signal generation means for generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; intermediate-image storage means for storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; prediction-coefficient storage means for storing a prediction coefficient linked to each class code; prediction-coefficient update means for generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and for updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage means; pixel-value update means for generating a more-appropriate pixel value of a focus pixel in the intermediate-image signal, according to the prediction coefficient linked to the class code linked to an aimed-at pixel selected based on the focus pixel in the intermediate-image signal, at least one aimed-at pixel selected based on the focus pixel in the intermediate-image signal, and the original-image signal, and for updating the pixel value of the focus pixel, stored in the intermediate-image storage means; and determination means for determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in still another aspect of the present invention through the provision of an image-signal conversion method for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, including an intermediate-image-signal generation step of generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; an intermediate-image storage step of storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a class-code update step of selecting a more appropriate class code linked to the aimed-at pixel in the intermediate-image signal, according to the intermediate-image signal, the prediction coefficient linked to the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, and the original-image signal, and of updating the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, stored in the intermediate-image storage step; and a determination step of determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in yet another aspect of the present invention through the provision of an image-signal conversion method for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, including an intermediate-image-signal generation step of generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; an intermediate-image storage step of storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a pixel-value update step of generating a more-appropriate pixel value of a focus pixel in the intermediate-image signal, according to the prediction coefficient linked to the class code linked to an aimed-at pixel selected based on the focus pixel in the intermediate-image signal, at least one aimed-at pixel selected based on the focus pixel in the intermediate-image signal, and the original-image signal, and of updating the pixel value of the focus pixel, stored in the intermediate-image storage step; and a determination step of determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in still yet another aspect of the present invention through the provision of a recording medium for storing a computer-controllable program for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, the program including an intermediate-image-signal generation step of generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; an intermediate-image storage step of storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a class-code update step of selecting a more appropriate class code linked to the aimed-at pixel in the intermediate-image signal, according to the intermediate-image signal, the prediction coefficient linked to the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, and the original-image signal, and of updating the class code linked to the pixel value of the aimed-at pixel in the intermediate-image signal, stored in the intermediate-image storage step; and a determination step of determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in a further aspect of the present invention through the provision of a recording medium for storing a computer-controllable program for converting an original-image signal to an output-image signal having a smaller amount of information than the original-image signal, the program including an intermediate-image-signal generation step of generating an intermediate-image signal having the same amount of information as the output-image signal, from the original-image signal; an intermediate-image storage step of storing the pixel value of each pixel of the intermediate-image signal, the pixel value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-image signal, the class code linked to an aimed-at pixel in the intermediate-image signal, and the original-image signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a pixel-value update step of generating a more-appropriate pixel value of a focus pixel in the intermediate-image signal, according to the prediction coefficient linked to the class code linked to an aimed-at pixel selected based on the focus pixel in the intermediate-image signal, at least one aimed-at pixel selected based on the focus pixel in the intermediate-image signal, and the original-image signal, and of updating the pixel value of the focus pixel, stored in the intermediate-image storage step; and a determination step of determining the intermediate-image signal as the output-image signal when a predetermined condition is satisfied.
The foregoing object is achieved in a still further aspect of the present invention through the provision of an information-signal conversion apparatus for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, including intermediate-information-signal generation means for generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; intermediate-information storage means for storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; prediction-coefficient storage means for storing a prediction coefficient linked to each class code; prediction-coefficient update means for generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and for updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage means; class-code update means for selecting a more appropriate class code linked to the aimed-at sample in the intermediate-information signal, according to the intermediate-information signal, the prediction coefficient linked to the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, and the original-information signal, and for updating the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, stored in the intermediate-information storage means; and determination means for determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a yet further aspect of the present invention through the provision of an information-signal conversion apparatus for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, including intermediate-information-signal generation means for generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; intermediate-information storage means for storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; prediction-coefficient storage means for storing a prediction coefficient linked to each class code; prediction-coefficient update means for generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and for updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage means; sample-value update means for generating a more-appropriate sample value of a focus sample in the intermediate-information signal, according to the prediction coefficient linked to the class code linked to an aimed-at sample selected based on the focus sample in the intermediate-information signal, at least one aimed-at sample selected based on the focus sample in the intermediate-information signal, and the original-information signal, and for updating the sample value of the focus sample, stored in the intermediate-information storage means; and determination means for determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a still yet further aspect of the present invention through the provision of an information-signal conversion method for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a class-code update step of selecting a more appropriate class code linked to the aimed-at sample in the intermediate-information signal, according to the intermediate-information signal, the prediction coefficient linked to the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, and the original-information signal, and of updating the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a different aspect of the present invention through the provision of an information-signal conversion method for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a sample-value update step of generating a more-appropriate sample value of a focus sample in the intermediate-information signal, according to the prediction coefficient linked to the class code linked to an aimed-at sample selected based on the focus sample in the intermediate-information signal, at least one aimed-at sample selected based on the focus sample in the intermediate-information signal, and the original-information signal, and of updating the sample value of the focus sample, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a still different aspect of the present invention through the provision of a recording medium for storing a computer-controllable program for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, the program including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a class-code update step of selecting a more appropriate class code linked to the aimed-at sample in the intermediate-information signal, according to the intermediate-information signal, the prediction coefficient linked to the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, and the original-information signal, and of updating the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a yet different aspect of the present invention through the provision of a recording medium for storing a computer-controllable program for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, the program including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a sample-value update step of generating a more-appropriate sample value of a focus sample in the intermediate-information signal, according to the prediction coefficient linked to the class code linked to an aimed-at sample selected based on the focus sample in the intermediate-information signal, at least one aimed-at sample selected based on the focus sample in the intermediate-information signal, and the original-information signal, and of updating the sample value of the focus sample, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a still yet different aspect of the present invention through the provision of a signal for carrying a computer-controllable program for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, the program including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a class-code update step of selecting a more appropriate class code linked to the aimed-at sample in the intermediate-information signal, according to the intermediate-information signal, the prediction coefficient linked to the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, and the original-information signal, and of updating the class code linked to the sample value of the aimed-at sample in the intermediate-information signal, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.
The foregoing object is achieved in a further different aspect of the present invention through the provision of a signal for carrying a computer-controllable program for converting an original-information signal to an output-information signal having a smaller amount of information than the original-information signal, the program including an intermediate-information-signal generation step of generating an intermediate-information signal having the same amount of information as the output-information signal, from the original-information signal; an intermediate-information storage step of storing the sample value of each sample of the intermediate-information signal, the sample value being linked to each class code; a prediction-coefficient storage step of storing a prediction coefficient linked to each class code; a prediction-coefficient update step of generating, according to the intermediate-information signal, the class code linked to an aimed-at sample in the intermediate-information signal, and the original-information signal, a more-appropriate prediction coefficient linked to the class code, and of updating the prediction coefficient linked to each class code, stored in the prediction-coefficient storage step; a sample-value update step of generating a more-appropriate sample value of a focus sample in the intermediate-information signal, according to the prediction coefficient linked to the class code linked to an aimed-at sample selected based on the focus sample in the intermediate-information signal, at least one aimed-at sample selected based on the focus sample in the intermediate-information signal, and the original-information signal, and of updating the sample value of the focus sample, stored in the intermediate-information storage step; and a determination step of determining the intermediate-information signal as the output-information signal when a predetermined condition is satisfied.